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/* gameplaySP
*
* Copyright (C) 2006 Exophase <exophase@gmail.com>
* Copyright (C) 2023 David Guillen Fandos <david@davidgf.net>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
extern "C" {
#include "common.h"
}
u16* gba_screen_pixels = NULL;
#define get_screen_pixels() gba_screen_pixels
#define get_screen_pitch() GBA_SCREEN_PITCH
typedef struct {
u16 attr0, attr1, attr2, attr3;
} t_oam;
typedef struct {
u16 pad0[3];
u16 dx;
u16 pad1[3];
u16 dmx;
u16 pad2[3];
u16 dy;
u16 pad3[3];
u16 dmy;
} t_affp;
typedef void (* bitmap_render_function)(u32 start, u32 end, void *dest_ptr);
typedef void (* tile_render_function)(u32 layer, u32 start, u32 end, void *dest_ptr);
typedef void (*conditional_render_function)(
u32 start, u32 end, u16 *scanline, u32 enable_flags);
typedef void (*window_render_function)(u16 *scanline, u32 start, u32 end);
static void render_conditional_tile(
u32 start, u32 end, u16 *scanline, u32 enable_flags);
static void render_conditional_bitmap(
u32 start, u32 end, u16 *scanline, u32 enable_flags);
typedef struct
{
bitmap_render_function blit_render;
bitmap_render_function scale_render;
bitmap_render_function affine_render;
} bitmap_layer_render_struct;
// Object blending modes
#define OBJ_MOD_NORMAL 0
#define OBJ_MOD_SEMITRAN 1
#define OBJ_MOD_WINDOW 2
#define OBJ_MOD_INVALID 3
// BLDCNT color effect modes
#define COL_EFFECT_NONE 0x0
#define COL_EFFECT_BLEND 0x1
#define COL_EFFECT_BRIGHT 0x2
#define COL_EFFECT_DARK 0x3
// Background render modes
#define RENDER_NORMAL 0
#define RENDER_COL16 1
#define RENDER_COL32 2
#define RENDER_ALPHA 3
// Byte lengths of complete tiles and tile rows in 4bpp and 8bpp.
#define tile_width_4bpp 4
#define tile_size_4bpp 32
#define tile_width_8bpp 8
#define tile_size_8bpp 64
// Sprite rendering cycles
#define REND_CYC_SCANLINE 1210
#define REND_CYC_REDUCED 954
// Generate bit mask (bits 9th and 10th) with information about the pixel
// status (1st and/or 2nd target) for later blending.
static inline u16 color_flags(u32 layer) {
u32 bldcnt = read_ioreg(REG_BLDCNT);
return (
((bldcnt >> layer) & 0x01) | // 1st target
((bldcnt >> (layer + 7)) & 0x02) // 2nd target
) << 9;
}
static const u32 map_widths[] = { 256, 512, 256, 512 };
typedef enum
{
FULLCOLOR, // Regular rendering, output a 16 bit color
INDXCOLOR, // Rendering to indexed color, so we can later apply dark/bright
STCKCOLOR, // Stacks two indexed pixels (+flags) to apply blending
PIXCOPY // Special mode used for sprites, to allow for obj-window drawing
} rendtype;
s32 affine_reference_x[2];
s32 affine_reference_y[2];
static inline s32 signext28(u32 value)
{
s32 ret = (s32)(value << 4);
return ret >> 4;
}
void video_reload_counters()
{
/* This happens every Vblank */
affine_reference_x[0] = signext28(read_ioreg32(REG_BG2X_L));
affine_reference_y[0] = signext28(read_ioreg32(REG_BG2Y_L));
affine_reference_x[1] = signext28(read_ioreg32(REG_BG3X_L));
affine_reference_y[1] = signext28(read_ioreg32(REG_BG3Y_L));
}
// Renders non-affine tiled background layer.
// Will process a full or partial tile (start and end within 0..8) and draw
// it in either 8 or 4 bpp mode. Honors vertical and horizontal flip.
// tile contains the tile info (contains tile index, flip bits, pal info)
// hflip causes the tile pixels lookup to be reversed (from MSB to LSB
// If isbase is not set, color 0 is interpreted as transparent, otherwise
// we are drawing the base layer, so palette[0] is used (backdrop).
template<typename dsttype, rendtype rdtype, bool is8bpp, bool isbase, bool hflip>
static inline void render_part_tile_Nbpp(u32 bg_comb, u32 px_comb,
dsttype *dest_ptr, u32 start, u32 end, u16 tile,
const u8 *tile_base, int vertical_pixel_flip
) {
// Seek to the specified tile, using the tile number and size.
// tile_base already points to the right tile-line vertical offset
const u8 *tile_ptr = &tile_base[(tile & 0x3FF) * (is8bpp ? 64 : 32)];
// On vertical flip, apply the mirror offset
if (tile & 0x800)
tile_ptr += vertical_pixel_flip;
if (is8bpp) {
// Each byte is a color, mapped to a palete. 8 bytes can be read as 64bit
for (u32 i = start; i < end; i++, dest_ptr++) {
// Honor hflip by selecting bytes in the correct order
u32 sel = hflip ? (7-i) : i;
u8 pval = tile_ptr[sel];
// Alhpa mode stacks previous value (unless rendering the first layer)
if (pval) {
if (rdtype == FULLCOLOR)
*dest_ptr = palette_ram_converted[pval];
else if (rdtype == INDXCOLOR)
*dest_ptr = pval | px_comb; // Add combine flags
else if (rdtype == STCKCOLOR)
// Stack pixels on top of the pixel value and combine flags
*dest_ptr = pval | px_comb | ((isbase ? bg_comb : *dest_ptr) << 16);
}
else if (isbase) {
if (rdtype == FULLCOLOR)
*dest_ptr = palette_ram_converted[0];
else
*dest_ptr = 0 | bg_comb; // Add combine flags
}
}
} else {
// In 4bpp mode, the tile[15..12] bits contain the sub-palette number.
u16 tilepal = (tile >> 12) << 4;
// Only 32 bits (8 pixels * 4 bits)
for (u32 i = start; i < end; i++, dest_ptr++) {
u32 selb = hflip ? (3-i/2) : i/2;
u32 seln = hflip ? ((i & 1) ^ 1) : (i & 1);
u8 pval = (tile_ptr[selb] >> (seln * 4)) & 0xF;
if (pval) {
if (rdtype == FULLCOLOR)
*dest_ptr = palette_ram_converted[tilepal | pval];
else if (rdtype == INDXCOLOR)
*dest_ptr = px_comb | tilepal | pval;
else if (rdtype == STCKCOLOR)
*dest_ptr = px_comb | tilepal | pval | ((isbase ? bg_comb : *dest_ptr) << 16); // Stack pixels
}
else if (isbase) {
if (rdtype == FULLCOLOR)
*dest_ptr = palette_ram_converted[0];
else
*dest_ptr = 0 | bg_comb;
}
}
}
}
// Same as above, but optimized for full tiles. Skip comments here.
template<typename dsttype, rendtype rdtype, bool is8bpp, bool isbase, bool hflip>
static inline void render_tile_Nbpp(
u32 bg_comb, u32 px_comb, dsttype *dest_ptr, u16 tile,
const u8 *tile_base, int vertical_pixel_flip
) {
const u8 *tile_ptr = &tile_base[(tile & 0x3FF) * (is8bpp ? 64 : 32)];
if (tile & 0x800)
tile_ptr += vertical_pixel_flip;
if (is8bpp) {
for (u32 j = 0; j < 2; j++) {
u32 tilepix = eswap32(((u32*)tile_ptr)[hflip ? 1-j : j]);
for (u32 i = 0; i < 4; i++, dest_ptr++) {
u8 pval = hflip ? (tilepix >> (24 - i*8)) : (tilepix >> (i*8));
if (pval) {
if (rdtype == FULLCOLOR)
*dest_ptr = palette_ram_converted[pval];
else if (rdtype == INDXCOLOR)
*dest_ptr = pval | px_comb; // Add combine flags
else if (rdtype == STCKCOLOR)
*dest_ptr = pval | px_comb | ((isbase ? bg_comb : *dest_ptr) << 16);
}
else if (isbase) {
if (rdtype == FULLCOLOR)
*dest_ptr = palette_ram_converted[0];
else
*dest_ptr = 0 | bg_comb; // Add combine flags
}
}
}
} else {
u16 tilepal = (tile >> 12) << 4;
u32 tilepix = eswap32(*(u32*)tile_ptr);
for (u32 i = 0; i < 8; i++, dest_ptr++) {
u8 pval = (hflip ? (tilepix >> ((7-i)*4)) : (tilepix >> (i*4))) & 0xF;
if (pval) {
if (rdtype == FULLCOLOR)
*dest_ptr = palette_ram_converted[tilepal | pval];
else if (rdtype == INDXCOLOR)
*dest_ptr = px_comb | tilepal | pval;
else if (rdtype == STCKCOLOR)
*dest_ptr = px_comb | tilepal | pval | ((isbase ? bg_comb : *dest_ptr) << 16); // Stack pixels
}
else if (isbase) {
if (rdtype == FULLCOLOR)
*dest_ptr = palette_ram_converted[0];
else
*dest_ptr = 0 | bg_comb;
}
}
}
}
template<typename stype, rendtype rdtype, bool isbase, bool is8bpp>
static void render_scanline_text(u32 layer,
u32 start, u32 end, void *scanline)
{
u32 bg_control = read_ioreg(REG_BGxCNT(layer));
u16 vcount = read_ioreg(REG_VCOUNT);
u32 map_size = (bg_control >> 14) & 0x03;
u32 map_width = map_widths[map_size];
u32 hoffset = (start + read_ioreg(REG_BGxHOFS(layer))) % 512;
u32 voffset = (vcount + read_ioreg(REG_BGxVOFS(layer))) % 512;
stype *dest_ptr = ((stype*)scanline) + start;
u32 i;
// Calculate combine masks. These store 2 bits of info: 1st and 2nd target.
// If set, the current pixel belongs to a layer that is 1st or 2nd target.
u32 bg_comb = color_flags(5);
u32 px_comb = color_flags(layer);
// Background map data is in vram, at an offset specified in 2K blocks.
// (each map data block is 32x32 tiles, at 16bpp, so 2KB)
u32 base_block = (bg_control >> 8) & 0x1F;
u16 *map_base = (u16 *)&vram[base_block * 2048];
u16 *map_ptr, *second_ptr;
end -= start;
// Skip the top one/two block(s) if using the bottom half
if ((map_size & 0x02) && (voffset >= 256))
map_base += ((map_width / 8) * 32);
// Skip the top tiles within the block
map_base += (((voffset % 256) / 8) * 32);
// we might need to render from two charblocks, store a second pointer.
second_ptr = map_ptr = map_base;
if(map_size & 0x01) // If background is 512 pixels wide
{
if(hoffset >= 256)
{
// If we are rendering the right block, skip a whole charblock
hoffset -= 256;
map_ptr += (32 * 32);
}
else
{
// If we are rendering the left block, we might overrun into the right
second_ptr += (32 * 32);
}
}
else
{
hoffset %= 256; // Background is 256 pixels wide
}
// Skip the left blocks within the block
map_ptr += hoffset / 8;
{
// Render a single scanline of text tiles
u32 tilewidth = is8bpp ? tile_width_8bpp : tile_width_4bpp;
u32 vert_pix_offset = (voffset % 8) * tilewidth;
// Calculate the pixel offset between a line and its "flipped" mirror.
// The values can be {56, 40, 24, 8, -8, -24, -40, -56}
s32 vflip_off = is8bpp ?
tile_size_8bpp - 2*vert_pix_offset - tile_width_8bpp :
tile_size_4bpp - 2*vert_pix_offset - tile_width_4bpp;
// The tilemap base is selected via bgcnt (16KiB chunks)
u32 tilecntrl = (bg_control >> 2) & 0x03;
// Account for the base offset plus the tile vertical offset
u8 *tile_base = &vram[tilecntrl * 16*1024 + vert_pix_offset];
// Number of pixels available until the end of the tile block
u32 pixel_run = 256 - hoffset;
u32 tile_hoff = hoffset % 8;
u32 partial_hcnt = 8 - tile_hoff;
if (tile_hoff) {
// First partial tile, only right side is visible.
u32 todraw = MIN(end, partial_hcnt); // [1..7]
u32 stop = tile_hoff + todraw; // Usually 8, unless short run.
u16 tile = eswap16(*map_ptr++);
if (tile & 0x400) // Tile horizontal flip
render_part_tile_Nbpp<stype, rdtype, is8bpp, isbase, true>(
bg_comb, px_comb, dest_ptr, tile_hoff, stop, tile, tile_base, vflip_off);
else
render_part_tile_Nbpp<stype, rdtype, is8bpp, isbase, false>(
bg_comb, px_comb, dest_ptr, tile_hoff, stop, tile, tile_base, vflip_off);
dest_ptr += todraw;
end -= todraw;
pixel_run -= todraw;
}
if (!end)
return;
// Now render full tiles
u32 todraw = MIN(end, pixel_run) / 8;
for (i = 0; i < todraw; i++) {
u16 tile = eswap16(*map_ptr++);
if (tile & 0x400) // Tile horizontal flip
render_tile_Nbpp<stype, rdtype, is8bpp, isbase, true>(
bg_comb, px_comb, &dest_ptr[i * 8], tile, tile_base, vflip_off);
else
render_tile_Nbpp<stype, rdtype, is8bpp, isbase, false>(
bg_comb, px_comb, &dest_ptr[i * 8], tile, tile_base, vflip_off);
}
end -= todraw * 8;
pixel_run -= todraw * 8;
dest_ptr += todraw * 8;
if (!end)
return;
// Switch to the next char block if we ran out of tiles
if (!pixel_run)
map_ptr = second_ptr;
todraw = end / 8;
if (todraw) {
for (i = 0; i < todraw; i++) {
u16 tile = eswap16(*map_ptr++);
if (tile & 0x400) // Tile horizontal flip
render_tile_Nbpp<stype, rdtype, is8bpp, isbase, true>(
bg_comb, px_comb, &dest_ptr[i * 8], tile, tile_base, vflip_off);
else
render_tile_Nbpp<stype, rdtype, is8bpp, isbase, false>(
bg_comb, px_comb, &dest_ptr[i * 8], tile, tile_base, vflip_off);
}
end -= todraw * 8;
dest_ptr += todraw * 8;
}
// Finalize the tile rendering the left side of it (from 0 up to "end").
if (end) {
u16 tile = eswap16(*map_ptr++);
if (tile & 0x400) // Tile horizontal flip
render_part_tile_Nbpp<stype, rdtype, is8bpp, isbase, true>(
bg_comb, px_comb, dest_ptr, 0, end, tile, tile_base, vflip_off);
else
render_part_tile_Nbpp<stype, rdtype, is8bpp, isbase, false>(
bg_comb, px_comb, dest_ptr, 0, end, tile, tile_base, vflip_off);
}
}
}
template<typename dsttype, rendtype rdtype, bool isbase>
static inline void render_pixel_8bpp(u32 layer,
dsttype *dest_ptr, u32 px, u32 py, u32 bg_comb, u32 px_comb,
const u8 *tile_base, const u8 *map_base, u32 map_size
) {
// Pitch represents the log2(number of tiles per row) (from 16 to 128)
u32 map_pitch = map_size + 4;
// Given coords (px,py) in the background space, find the tile.
u32 mapoff = (px / 8) + ((py / 8) << map_pitch);
// Each tile is 8x8, so 64 bytes each.
const u8 *tile_ptr = &tile_base[map_base[mapoff] * tile_size_8bpp];
// Read the 8bit color within the tile.
u8 pval = tile_ptr[(px % 8) + ((py % 8) * 8)];
// Alhpa mode stacks previous value (unless rendering the first layer)
if (pval) {
if (rdtype == FULLCOLOR)
*dest_ptr = palette_ram_converted[pval];
else if (rdtype == INDXCOLOR)
*dest_ptr = pval | px_comb; // Add combine flags
else if (rdtype == STCKCOLOR)
// Stack pixels. If base, stack the base pixel.
*dest_ptr = pval | px_comb | ((isbase ? bg_comb : *dest_ptr) << 16);
}
else if (isbase) {
// Transparent pixel, but we are base layer, so render background.
if (rdtype == FULLCOLOR)
*dest_ptr = palette_ram_converted[0];
else
*dest_ptr = 0 | bg_comb; // Just backdrop color and combine flags
}
}
template<typename dsttype, rendtype rdtype>
static inline void render_bdrop_pixel_8bpp(dsttype *dest_ptr, u32 bg_comb) {
// Alhpa mode stacks previous value (unless rendering the first layer)
if (rdtype == FULLCOLOR)
*dest_ptr = palette_ram_converted[0];
else
*dest_ptr = 0 | bg_comb;
}
// Affine background rendering logic.
// wrap extends the background infinitely, otherwise transparent/backdrop fill
// rotate indicates if there's any rotation (optimized version for no-rotation)
template <typename dsttype, rendtype rdtype, bool isbase, bool wrap, bool rotate>
static inline void render_affine_background(
u32 layer, u32 start, u32 cnt, const u8 *map_base,
u32 map_size, const u8 *tile_base, dsttype *dst_ptr) {
// Backdrop and current layer combine bits.
u32 bg_comb = color_flags(5);
u32 px_comb = color_flags(layer);
s32 dx = (s16)read_ioreg(REG_BGxPA(layer));
s32 dy = (s16)read_ioreg(REG_BGxPC(layer));
s32 source_x = affine_reference_x[layer - 2] + (start * dx);
s32 source_y = affine_reference_y[layer - 2] + (start * dy);
// Maps are squared, four sizes available (128x128 to 1024x1024)
u32 width_height = 128 << map_size;
if (wrap) {
// In wrap mode the entire space is covered, since it "wraps" at the edges
while (cnt--) {
u32 pixel_x = (u32)(source_x >> 8) & (width_height-1);
u32 pixel_y = (u32)(source_y >> 8) & (width_height-1);
// Lookup pixel and draw it.
render_pixel_8bpp<dsttype, rdtype, isbase>(
layer, dst_ptr++, pixel_x, pixel_y, bg_comb, px_comb,
tile_base, map_base, map_size);
// Move to the next pixel, update coords accordingly
source_x += dx;
if (rotate)
source_y += dy;
}
} else {
// Early optimization if Y-coord is out completely for this line.
// (if there's no rotation Y coord remains identical throughout the line).
bool is_y_out = !rotate && ((u32)(source_y >> 8)) >= width_height;
if (!is_y_out) {
// Draw backdrop pixels if necessary until we reach the background edge.
// TODO: on non-base cases this could perhaps be calculated in O(1)?
while (cnt) {
// Draw backdrop pixels if they lie outside of the background.
u32 pixel_x = (u32)(source_x >> 8), pixel_y = (u32)(source_y >> 8);
// Stop once we find a pixel that is actually *inside* the map.
if (pixel_x < width_height && pixel_y < width_height)
break;
// Draw a backdrop pixel if we are the base layer.
if (isbase)
render_bdrop_pixel_8bpp<dsttype, rdtype>(dst_ptr, bg_comb);
dst_ptr++;
source_x += dx;
if (rotate)
source_y += dy;
cnt--;
}
// Draw background pixels by looking them up in the map
while (cnt) {
u32 pixel_x = (u32)(source_x >> 8), pixel_y = (u32)(source_y >> 8);
// Check if we run out of background pixels, stop drawing.
if (pixel_x >= width_height || pixel_y >= width_height)
break;
// Lookup pixel and draw it.
render_pixel_8bpp<dsttype, rdtype, isbase>(
layer, dst_ptr++, pixel_x, pixel_y, bg_comb, px_comb,
tile_base, map_base, map_size);
// Move to the next pixel, update coords accordingly
cnt--;
source_x += dx;
if (rotate)
source_y += dy;
}
}
// Complete the line on the right, if we ran out over the bg edge.
// Only necessary for the base layer, otherwise we can safely finish.
if (isbase)
while (cnt--)
render_bdrop_pixel_8bpp<dsttype, rdtype>(dst_ptr++, bg_comb);
}
}
// Renders affine backgrounds. These differ substantially from non-affine
// ones. Tile maps are byte arrays (instead of 16 bit), limiting the map to
// 256 different tiles (with no flip bits and just one single 256 color pal).
template<typename dsttype, rendtype rdtype, bool isbase>
static void render_scanline_affine(u32 layer,
u32 start, u32 end, void *scanline)
{
u32 bg_control = read_ioreg(REG_BGxCNT(layer));
u32 map_size = (bg_control >> 14) & 0x03;
// Char block base pointer
u32 base_block = (bg_control >> 8) & 0x1F;
u8 *map_base = &vram[base_block * 2048];
// The tilemap base is selected via bgcnt (16KiB chunks)
u32 tilecntrl = (bg_control >> 2) & 0x03;
u8 *tile_base = &vram[tilecntrl * 16*1024];
dsttype *dest_ptr = ((dsttype*)scanline) + start;
bool has_rotation = read_ioreg(REG_BGxPC(layer)) != 0;
bool has_wrap = (bg_control >> 13) & 1;
// Four specialized versions for faster rendering on specific cases like
// scaling only or non-wrapped backgrounds.
if (has_wrap) {
if (has_rotation)
render_affine_background<dsttype, rdtype, isbase, true, true>(
layer, start, end - start, map_base, map_size, tile_base, dest_ptr);
else
render_affine_background<dsttype, rdtype, isbase, true, false>(
layer, start, end - start, map_base, map_size, tile_base, dest_ptr);
} else {
if (has_rotation)
render_affine_background<dsttype, rdtype, isbase, false, true>(
layer, start, end - start, map_base, map_size, tile_base, dest_ptr);
else
render_affine_background<dsttype, rdtype, isbase, false, false>(
layer, start, end - start, map_base, map_size, tile_base, dest_ptr);
}
}
// Renders a bitmap honoring the pixel mode and any affine transformations.
// There's optimized versions for bitmaps without scaling / rotation.
template<unsigned mode, typename pixfmt, unsigned width, unsigned height, bool scale, bool rotate>
static inline void render_scanline_bitmap(u32 start, u32 end, void *scanline) {
// Modes 4 and 5 feature double buffering.
bool second_frame = (mode >= 4) && (read_ioreg(REG_DISPCNT) & 0x10);
pixfmt *src_ptr = (pixfmt*)&vram[second_frame ? 0xA000 : 0x0000];
u16 *dst_ptr = ((u16*)scanline) + start;
s32 dx = (s16)read_ioreg(REG_BG2PA);
s32 dy = (s16)read_ioreg(REG_BG2PC);
s32 source_x = affine_reference_x[0] + (start * dx); // Always BG2
s32 source_y = affine_reference_y[0] + (start * dy);
// Premature abort render optimization if bitmap out of Y coordinate.
bool is_y_out = !rotate && ((u32)(source_y >> 8)) >= height;
if (is_y_out)
return;
if (!scale) {
// Pretty much a blit onto the output buffer.
// Skip to the X pixel (dest) and start copying (drawing really)
if (source_x < 0) {
// TODO: Not sure if the math is OK for non-integer offsets
u32 delta = (-source_x + 255) >> 8;
dst_ptr += delta;
start += delta;
source_x += delta << 8;
}
u32 pixel_y = (u32)(source_y >> 8);
u32 pixel_x = (u32)(source_x >> 8);
while (start < end && pixel_x < width) {
// Pretty much pixel copier
pixfmt *valptr = &src_ptr[pixel_x + (pixel_y * width)];
pixfmt val = sizeof(pixfmt) == 2 ? eswap16(*valptr) : *valptr;
if (mode != 4)
*dst_ptr = convert_palette(val); // Direct color
else if (val)
*dst_ptr = palette_ram_converted[val]; // Indexed color
// Move to the next pixel, update coords accordingly
start++;
dst_ptr++;
pixel_x++;
}
} else {
// Look for the first pixel to be drawn.
// TODO This can be calculated in O(1), at least for non-rotation
while (start < end) {
u32 pixel_x = (u32)(source_x >> 8), pixel_y = (u32)(source_y >> 8);
// Stop once we find a pixel that is actually *inside*
if (pixel_x < width && pixel_y < height)
break;
dst_ptr++;
source_x += dx;
if (rotate)
source_y += dy;
start++;
}
// Draw background pixels by looking them up in the map
while (start < end) {
u32 pixel_x = (u32)(source_x >> 8), pixel_y = (u32)(source_y >> 8);
// Check if we run out of background pixels, stop drawing.
if (pixel_x >= width || pixel_y >= height)
break;
// Lookup pixel and draw it.
pixfmt *valptr = &src_ptr[pixel_x + (pixel_y * width)];
pixfmt val = sizeof(pixfmt) == 2 ? eswap16(*valptr) : *valptr;
if (mode != 4)
*dst_ptr = convert_palette(val); // Direct color
else if (val)
*dst_ptr = palette_ram_converted[val]; // Indexed color
// Move to the next pixel, update coords accordingly
start++;
dst_ptr++;
source_x += dx;
if (rotate)
source_y += dy;
}
}
}
// Fill in the renderers for a layer based on the mode type,
#define bitmap_layer_render_functions(mode, ttype, w, h) \
{ \
render_scanline_bitmap<mode, ttype, w, h, false, false>, \
render_scanline_bitmap<mode, ttype, w, h, true, false>, \
render_scanline_bitmap<mode, ttype, w, h, true, true>, \
} \
static const bitmap_layer_render_struct bitmap_mode_renderers[3] =
{
bitmap_layer_render_functions(3, u16, 240, 160),
bitmap_layer_render_functions(4, u8, 240, 160),
bitmap_layer_render_functions(5, u16, 160, 128)
};
// Object/Sprite rendering logic
static const u8 obj_dim_table[3][4][2] = {
{ {8, 8}, {16, 16}, {32, 32}, {64, 64} },
{ {16, 8}, {32, 8}, {32, 16}, {64, 32} },
{ {8, 16}, {8, 32}, {16, 32}, {32, 64} }
};
static u8 obj_priority_list[5][160][128];
static u8 obj_priority_count[5][160];
static u8 obj_alpha_count[160];
typedef struct {
s32 obj_x, obj_y;
s32 obj_w, obj_h;
u32 attr1, attr2;
bool is_double;
} t_sprite;
// Renders a tile row (8 pixels) for a regular (non-affine) object/sprite.
// tile_offset points to the VRAM offset where the data lives.
template<typename dsttype, rendtype rdtype, bool is8bpp, bool hflip>
static inline void render_obj_part_tile_Nbpp(u32 px_comb,
dsttype *dest_ptr, u32 start, u32 end, u32 tile_offset, u16 palette
) {
// Note that the last VRAM bank wrap around, hence the offset aliasing
const u8* tile_ptr = &vram[0x10000 + (tile_offset & 0x7FFF)];
if (is8bpp) {
// Each byte is a color, mapped to a palete.
for (u32 i = start; i < end; i++, dest_ptr++) {
// Honor hflip by selecting bytes in the correct order
u32 sel = hflip ? (7-i) : i;
u8 pval = tile_ptr[sel];
// Alhpa mode stacks previous value
if (pval) {
if (rdtype == FULLCOLOR)
*dest_ptr = palette_ram_converted[pval | 0x100];
else if (rdtype == INDXCOLOR)
*dest_ptr = pval | px_comb | 0x100; // Add combine flags
else if (rdtype == STCKCOLOR) {
// Stack pixels on top of the pixel value and combine flags
// We do not stack OBJ on OBJ, rather overwrite the previous object
if (*dest_ptr & 0x100)
*dest_ptr = pval | px_comb | 0x100 | ((*dest_ptr) & 0xFFFF0000);
else
*dest_ptr = pval | px_comb | 0x100 | ((*dest_ptr) << 16);
}
else if (rdtype == PIXCOPY)
*dest_ptr = dest_ptr[240];
}
}
} else {
// Only 32 bits (8 pixels * 4 bits)
for (u32 i = start; i < end; i++, dest_ptr++) {
u32 selb = hflip ? (3-i/2) : i/2;
u32 seln = hflip ? ((i & 1) ^ 1) : (i & 1);
u8 pval = (tile_ptr[selb] >> (seln * 4)) & 0xF;
if (pval) {
u8 colidx = pval | palette;
if (rdtype == FULLCOLOR)
*dest_ptr = palette_ram_converted[colidx | 0x100];
else if (rdtype == INDXCOLOR)
*dest_ptr = colidx | px_comb | 0x100;
else if (rdtype == STCKCOLOR) {
if (*dest_ptr & 0x100)
*dest_ptr = colidx | px_comb | 0x100 | ((*dest_ptr) & 0xFFFF0000);
else
*dest_ptr = colidx | px_comb | 0x100 | ((*dest_ptr) << 16); // Stack pixels
}
else if (rdtype == PIXCOPY)
*dest_ptr = dest_ptr[240];
}
}
}
}
// Same as above but optimized for full tiles
template<typename dsttype, rendtype rdtype, bool is8bpp, bool hflip>
static inline void render_obj_tile_Nbpp(u32 px_comb,
dsttype *dest_ptr, u32 tile_offset, u16 palette
) {
const u8* tile_ptr = &vram[0x10000 + (tile_offset & 0x7FFF)];
if (is8bpp) {
for (u32 j = 0; j < 2; j++) {
u32 tilepix = eswap32(((u32*)tile_ptr)[hflip ? 1-j : j]);
for (u32 i = 0; i < 4; i++, dest_ptr++) {
u8 pval = hflip ? (tilepix >> (24 - i*8)) : (tilepix >> (i*8));
if (pval) {
if (rdtype == FULLCOLOR)
*dest_ptr = palette_ram_converted[pval | 0x100];
else if (rdtype == INDXCOLOR)
*dest_ptr = pval | px_comb | 0x100; // Add combine flags
else if (rdtype == STCKCOLOR) {
if (*dest_ptr & 0x100)
*dest_ptr = pval | px_comb | 0x100 | ((*dest_ptr) & 0xFFFF0000);
else
*dest_ptr = pval | px_comb | 0x100 | ((*dest_ptr) << 16);
}
else if (rdtype == PIXCOPY)
*dest_ptr = dest_ptr[240];
}
}
}
} else {
u32 tilepix = eswap32(*(u32*)tile_ptr);
for (u32 i = 0; i < 8; i++, dest_ptr++) {
u8 pval = (hflip ? (tilepix >> ((7-i)*4)) : (tilepix >> (i*4))) & 0xF;
if (pval) {
u8 colidx = pval | palette;
if (rdtype == FULLCOLOR)
*dest_ptr = palette_ram_converted[colidx | 0x100];
else if (rdtype == INDXCOLOR)
*dest_ptr = colidx | px_comb | 0x100;
else if (rdtype == STCKCOLOR) {
if (*dest_ptr & 0x100)
*dest_ptr = colidx | px_comb | 0x100 | ((*dest_ptr) & 0xFFFF0000);
else
*dest_ptr = colidx | px_comb | 0x100 | ((*dest_ptr) << 16); // Stack pixels
}
else if (rdtype == PIXCOPY)
*dest_ptr = dest_ptr[240];
}
}
}
}
// Renders a regular sprite (non-affine) row to screen.
// delta_x is the object X coordinate referenced from the window start.
// cnt is the maximum number of pixels to draw, honoring window, obj width, etc.
template <typename stype, rendtype rdtype, bool is8bpp, bool hflip>
static void render_object(
s32 delta_x, u32 cnt, stype *dst_ptr, u32 tile_offset, u32 px_comb, u16 palette
) {
// Tile size in bytes for each mode
const u32 tile_bsize = is8bpp ? tile_size_8bpp : tile_size_4bpp;
// Number of bytes to advance (or rewind) on the tile map
const s32 tile_size_off = hflip ? -tile_bsize : tile_bsize;
if (delta_x < 0) { // Left part is outside of the screen/window.
u32 offx = -delta_x; // How many pixels did we skip from the object?
s32 block_off = offx / 8;
u32 tile_off = offx % 8;
// Skip the first object tiles (skips in the flip direction)
tile_offset += block_off * tile_size_off;
// Render a partial tile to the left
if (tile_off) {
u32 residual = 8 - tile_off; // Pixel count to complete the first tile
u32 maxpix = MIN(residual, cnt);
render_obj_part_tile_Nbpp<stype, rdtype, is8bpp, hflip>(
px_comb, dst_ptr, tile_off, tile_off + maxpix, tile_offset, palette);
// Move to the next tile
tile_offset += tile_size_off;
// Account for drawn pixels
cnt -= maxpix;
dst_ptr += maxpix;
}
} else {
// Render object completely from the left. Skip the empty space to the left
dst_ptr += delta_x;
}
// Render full tiles to the scan line.
s32 num_tiles = cnt / 8;
while (num_tiles--) {
// Render full tiles
render_obj_tile_Nbpp<stype, rdtype, is8bpp, hflip>(px_comb, dst_ptr, tile_offset, palette);
tile_offset += tile_size_off;
dst_ptr += 8;
}
// Render any partial tile on the end
cnt = cnt % 8;
if (cnt)
render_obj_part_tile_Nbpp<stype, rdtype, is8bpp, hflip>(
px_comb, dst_ptr, 0, cnt, tile_offset, palette);
}
// Renders an affine sprite row to screen.
template <typename stype, rendtype rdtype, bool is8bpp, bool rotate>
static void render_affine_object(
const t_sprite *obji, const t_affp *affp, bool is_double,
u32 start, u32 end, stype *dst_ptr, u32 base_tile, u32 pxcomb, u16 palette
) {
// Tile size in bytes for each mode
const u32 tile_bsize = is8bpp ? tile_size_8bpp : tile_size_4bpp;
const u32 tile_bwidth = is8bpp ? tile_width_8bpp : tile_width_4bpp;
// Affine params
s32 dx = (s16)eswap16(affp->dx);
s32 dy = (s16)eswap16(affp->dy);
s32 dmx = (s16)eswap16(affp->dmx);
s32 dmy = (s16)eswap16(affp->dmy);
// Object dimensions and boundaries
u32 obj_dimw = obji->obj_w;
u32 obj_dimh = obji->obj_h;
s32 middle_x = is_double ? obji->obj_w : (obji->obj_w / 2);
s32 middle_y = is_double ? obji->obj_h : (obji->obj_h / 2);
s32 obj_width = is_double ? obji->obj_w * 2 : obji->obj_w;
s32 obj_height = is_double ? obji->obj_h * 2 : obji->obj_h;
s32 vcount = read_ioreg(REG_VCOUNT);
s32 y_delta = vcount - (obji->obj_y + middle_y);
if (obji->obj_x < (signed)start)
middle_x -= (start - obji->obj_x);
s32 source_x = (obj_dimw << 7) + (y_delta * dmx) - (middle_x * dx);
s32 source_y = (obj_dimh << 7) + (y_delta * dmy) - (middle_x * dy);
// Early optimization if Y-coord is out completely for this line.
// (if there's no rotation Y coord remains identical throughout the line).
if (!rotate && ((u32)(source_y >> 8)) >= (u32)obj_height)
return;
u32 d_start = MAX((signed)start, obji->obj_x);
u32 d_end = MIN((signed)end, obji->obj_x + obj_width);
u32 cnt = d_end - d_start;
dst_ptr += d_start;
bool obj1dmap = read_ioreg(REG_DISPCNT) & 0x40;
const u32 tile_pitch = obj1dmap ? (obj_dimw / 8) * tile_bsize : 1024;
// Skip pixels outside of the sprite area, until we reach the sprite "inside"
while (cnt) {
u32 pixel_x = (u32)(source_x >> 8), pixel_y = (u32)(source_y >> 8);
// Stop once we find a pixel that is actually *inside* the map.
if (pixel_x < obj_dimw && pixel_y < obj_dimh)
break;
dst_ptr++;
source_x += dx;
if (rotate)
source_y += dy;
cnt--;
}
// Draw sprite pixels by looking them up first. Lookup address is tricky!
while (cnt) {
u32 pixel_x = (u32)(source_x >> 8), pixel_y = (u32)(source_y >> 8);
// Check if we run out of the sprite, then we can safely abort.
if (pixel_x >= obj_dimw || pixel_y >= obj_dimh)
return;
// Lookup pixel and draw it.
u8 pixval;
if (is8bpp) {
// We lookup the byte directly and render it.
const u32 tile_off =
base_tile + // Character base
((pixel_y >> 3) * tile_pitch) + // Skip vertical blocks
((pixel_x >> 3) * tile_bsize) + // Skip horizontal blocks
((pixel_y & 0x7) * tile_bwidth) + // Skip vertical rows to the pixel
(pixel_x & 0x7); // Skip the horizontal offset
pixval = vram[0x10000 + (tile_off & 0x7FFF)]; // Read pixel value!
} else {
const u32 tile_off =
base_tile + // Character base
((pixel_y >> 3) * tile_pitch) + // Skip vertical blocks
((pixel_x >> 3) * tile_bsize) + // Skip horizontal blocks
((pixel_y & 0x7) * tile_bwidth) + // Skip vertical rows to the pixel
((pixel_x >> 1) & 0x3); // Skip the horizontal offset
u8 pixpair = vram[0x10000 + (tile_off & 0x7FFF)]; // Read two pixels (4bit each)
pixval = ((pixel_x & 1) ? pixpair >> 4 : pixpair & 0xF);
}
// Render the pixel value
if (pixval) {
if (rdtype == FULLCOLOR)
*dst_ptr = palette_ram_converted[pixval | palette | 0x100];
else if (rdtype == INDXCOLOR)
*dst_ptr = pixval | palette | 0x100 | pxcomb; // Add combine flags
else if (rdtype == STCKCOLOR) {
// Stack pixels on top of the pixel value and combine flags
if (*dst_ptr & 0x100)
*dst_ptr = pixval | palette | 0x100 | pxcomb | ((*dst_ptr) & 0xFFFF0000);
else
*dst_ptr = pixval | palette | 0x100 | pxcomb | ((*dst_ptr) << 16); // Stack pixels
}
else if (rdtype == PIXCOPY)
*dst_ptr = dst_ptr[240];
}
// Move to the next pixel, update coords accordingly
cnt--;
dst_ptr++;
source_x += dx;
if (rotate)
source_y += dy;
}
}
// Renders a single sprite on the current scanline
template <typename stype, rendtype rdtype, bool is8bpp>
inline static void render_sprite(
const t_sprite *obji, bool is_affine, u32 start, u32 end, stype *scanline, u32 pxcomb
) {
s32 vcount = read_ioreg(REG_VCOUNT);
bool obj1dmap = read_ioreg(REG_DISPCNT) & 0x40;
const u32 msk = is8bpp && !obj1dmap ? 0x3FE : 0x3FF;
const u32 base_tile = (obji->attr2 & msk) * 32;
// Render the object scanline using the correct mode.
// (in 4bpp mode calculate the palette number)
// Objects use the higher palette part
u16 pal = (is8bpp ? 0 : ((obji->attr2 >> 8) & 0xF0));
if (is_affine) {
u32 pnum = (obji->attr1 >> 9) & 0x1f;
const t_affp *affp_base = (t_affp*)oam_ram;
const t_affp *affp = &affp_base[pnum];
if (affp->dy == 0) // No rotation happening (just scale)
render_affine_object<stype, rdtype, is8bpp, false>(
obji, affp, obji->is_double, start, end, scanline, base_tile, pxcomb, pal);
else // Full rotation and scaling
render_affine_object<stype, rdtype, is8bpp, true>(
obji, affp, obji->is_double, start, end, scanline, base_tile, pxcomb, pal);
} else {
// The object could be out of the window, check and skip.
if (obji->obj_x >= (signed)end || obji->obj_x + obji->obj_w <= (signed)start)
return;
// Non-affine objects can be flipped on both edges.
bool hflip = obji->attr1 & 0x1000;
bool vflip = obji->attr1 & 0x2000;
// Calulate the vertical offset (row) to be displayed. Account for vflip.
u32 voffset = vflip ? obji->obj_y + obji->obj_h - vcount - 1 : vcount - obji->obj_y;
// Calculate base tile for the object (points to the row to be drawn).
u32 tile_bsize = is8bpp ? tile_size_8bpp : tile_size_4bpp;
u32 tile_bwidth = is8bpp ? tile_width_8bpp : tile_width_4bpp;
u32 obj_pitch = obj1dmap ? (obji->obj_w / 8) * tile_bsize : 1024;
u32 hflip_off = hflip ? ((obji->obj_w / 8) - 1) * tile_bsize : 0;
// Calculate the pointer to the tile.
const u32 tile_offset =
base_tile + // Char offset
(voffset / 8) * obj_pitch + // Select tile row offset
(voffset % 8) * tile_bwidth + // Skip tile rows
hflip_off; // Account for horizontal flip
// Make everything relative to start
s32 obj_x_offset = obji->obj_x - start;
u32 clipped_width = obj_x_offset >= 0 ? obji->obj_w : obji->obj_w + obj_x_offset;
u32 max_range = obj_x_offset >= 0 ? end - obji->obj_x : end - start;
u32 max_draw = MIN(max_range, clipped_width);
if (hflip)
render_object<stype, rdtype, is8bpp, true>(
obj_x_offset, max_draw, &scanline[start], tile_offset, pxcomb, pal);
else
render_object<stype, rdtype, is8bpp, false>(
obj_x_offset, max_draw, &scanline[start], tile_offset, pxcomb, pal);
}
}
// Renders objects on a scanline for a given priority.
template <typename stype, rendtype rdtype>
static void render_scanline_objs(
u32 priority, u32 start, u32 end, void *raw_ptr
) {
stype *scanline = (stype*)raw_ptr;
s32 vcount = read_ioreg(REG_VCOUNT);
s32 objn;
u32 objcnt = obj_priority_count[priority][vcount];
u8 *objlist = obj_priority_list[priority][vcount];
// Render all the visible objects for this priority (back to front)
for (objn = objcnt-1; objn >= 0; objn--) {
// Objects in the list are pre-filtered and sorted in the appropriate order
u32 objoff = objlist[objn];
const t_oam *oamentry = &((t_oam*)oam_ram)[objoff];
u16 obj_attr0 = eswap16(oamentry->attr0);
u16 obj_attr1 = eswap16(oamentry->attr1);
u16 obj_shape = obj_attr0 >> 14;
u16 obj_size = (obj_attr1 >> 14);
bool is_affine = obj_attr0 & 0x100;
bool is_trans = ((obj_attr0 >> 10) & 0x3) == OBJ_MOD_SEMITRAN;
bool is_8bpp = (obj_attr0 & 0x2000) != 0;
t_sprite obji = {
.obj_x = (s32)(obj_attr1 << 23) >> 23,
.obj_y = obj_attr0 & 0xFF,
.obj_w = obj_dim_table[obj_shape][obj_size][0],
.obj_h = obj_dim_table[obj_shape][obj_size][1],
.attr1 = obj_attr1,
.attr2 = eswap16(oamentry->attr2),
.is_double = (obj_attr0 & 0x200) != 0,
};
s32 obj_maxw = (is_affine && obji.is_double) ? obji.obj_w * 2 : obji.obj_w;
// The object could be out of the window, check and skip.
if (obji.obj_x >= (signed)end || obji.obj_x + obj_maxw <= (signed)start)
continue;
// ST-OBJs force 1st target bit (forced blending)
bool forcebld = is_trans && rdtype != FULLCOLOR;
if (obji.obj_y > 160)
obji.obj_y -= 256;
// In PIXCOPY mode, we have already some stuff rendered (winout) and now
// we render the "win-in" area for this object. The PIXCOPY function will
// copy (merge) the two pixels depending on the result of the sprite render
// The temporary buffer is rendered on the next scanline area.
if (rdtype == PIXCOPY) {
u32 sec_start = MAX((signed)start, obji.obj_x);
u32 sec_end = MIN((signed)end, obji.obj_x + obj_maxw);
u32 obj_enable = read_ioreg(REG_WINOUT) >> 8;
// Render at the next scanline!
u16 *tmp_ptr = (u16*)&scanline[GBA_SCREEN_PITCH];
if((read_ioreg(REG_DISPCNT) & 0x07) < 3)
render_conditional_tile(sec_start, sec_end, tmp_ptr, obj_enable);
else
render_conditional_bitmap(sec_start, sec_end, tmp_ptr, obj_enable);
}
// Calculate combine masks. These store 2 bits of info: 1st and 2nd target.
// If set, the current pixel belongs to a layer that is 1st or 2nd target.
// For ST-objs, we set an extra bit, for later blending.
u32 pxcomb = (forcebld ? 0x800 : 0) | color_flags(4);
if (is_8bpp)
render_sprite<stype, rdtype, true>(
&obji, is_affine, start, end, scanline, pxcomb);
else
render_sprite<stype, rdtype, false>(
&obji, is_affine, start, end, scanline, pxcomb);
}
}
// Goes through the object list in the OAM (from #127 to #0) and adds objects
// into a sorted list by priority for the current row.
// Invisible objects are discarded.
static void order_obj(u32 video_mode)
{
u32 obj_num;
u32 row;
t_oam *oam_base = (t_oam*)oam_ram;
u16 rend_cycles[160];
memset(obj_priority_count, 0, sizeof(obj_priority_count));
memset(obj_alpha_count, 0, sizeof(obj_alpha_count));
memset(rend_cycles, 0, sizeof(rend_cycles));
for(obj_num = 0; obj_num < 128; obj_num++)
{
t_oam *oam_ptr = &oam_base[obj_num];
u16 obj_attr0 = eswap16(oam_ptr->attr0);
// Bit 9 disables regular sprites. Used as double bit for affine ones.
bool visible = (obj_attr0 & 0x0300) != 0x0200;
if (visible) {
u16 obj_shape = obj_attr0 >> 14;
u32 obj_mode = (obj_attr0 >> 10) & 0x03;
// Prohibited shape and mode
bool invalid = (obj_shape == 0x3) || (obj_mode == OBJ_MOD_INVALID);
if (!invalid) {
u16 obj_attr1 = eswap16(oam_ptr->attr1);
u16 obj_attr2 = eswap16(oam_ptr->attr2);
u32 obj_priority = (obj_attr2 >> 10) & 0x03;
if (((video_mode < 3) || ((obj_attr2 & 0x3FF) >= 512)))
{
// Calculate object size (from size and shape attr bits)
u16 obj_size = (obj_attr1 >> 14);
s32 obj_height = obj_dim_table[obj_shape][obj_size][1];
s32 obj_width = obj_dim_table[obj_shape][obj_size][0];
s32 obj_y = obj_attr0 & 0xFF;
if(obj_y > 160)
obj_y -= 256;
// Double size for affine sprites with double bit set
if(obj_attr0 & 0x200)
{
obj_height *= 2;
obj_width *= 2;
}
if(((obj_y + obj_height) > 0) && (obj_y < 160))
{
s32 obj_x = (s32)(obj_attr1 << 23) >> 23;
if(((obj_x + obj_width) > 0) && (obj_x < 240))
{
bool is_affine = obj_attr0 & 0x100;
// Clip Y coord and height to the 0..159 interval
u32 starty = MAX(obj_y, 0);
u32 endy = MIN(obj_y + obj_height, 160);
// Calculate needed cycles to render the sprite
u16 cyccnt = is_affine ? (10 + obj_width * 2) : obj_width;
switch (obj_mode) {
case OBJ_MOD_SEMITRAN:
for(row = starty; row < endy; row++)
{
if (rend_cycles[row] < REND_CYC_SCANLINE) {
u32 cur_cnt = obj_priority_count[obj_priority][row];
obj_priority_list[obj_priority][row][cur_cnt] = obj_num;
obj_priority_count[obj_priority][row] = cur_cnt + 1;
rend_cycles[row] += cyccnt;
// Mark the row as having semi-transparent objects
obj_alpha_count[row] = 1;
}
}
break;
case OBJ_MOD_WINDOW:
obj_priority = 4;
/* fallthrough */
case OBJ_MOD_NORMAL:
// Add the object to the list.
for(row = starty; row < endy; row++)
{
if (rend_cycles[row] < REND_CYC_SCANLINE) {
u32 cur_cnt = obj_priority_count[obj_priority][row];
obj_priority_list[obj_priority][row][cur_cnt] = obj_num;
obj_priority_count[obj_priority][row] = cur_cnt + 1;
rend_cycles[row] += cyccnt;
}
}
break;
};
}
}
}
}
}
}
}
u32 layer_order[16];
u32 layer_count;
// Sorts active BG/OBJ layers and generates an ordered list of layers.
// Things are drawn back to front, so lowest priority goes first.
static void order_layers(u32 layer_flags, u32 vcnt)
{
bool obj_enabled = (layer_flags & 0x10);
s32 priority;
layer_count = 0;
for(priority = 3; priority >= 0; priority--)
{
bool anyobj = obj_priority_count[priority][vcnt] > 0;
s32 lnum;
for(lnum = 3; lnum >= 0; lnum--)
{
if(((layer_flags >> lnum) & 1) &&
((read_ioreg(REG_BGxCNT(lnum)) & 0x03) == priority))
{
layer_order[layer_count++] = lnum;
}
}
if(obj_enabled && anyobj)
layer_order[layer_count++] = priority | 0x04;
}
}
// Blending is performed by separating an RGB value into 0G0R0B (32 bit)
// Since blending factors are at most 16, mult/add operations do not overflow
// to the neighbouring color and can be performed much faster than separatedly
// Here follow the mask value to separate/expand the color to 32 bit,
// the mask to detect overflows in the blend operation and
#define BLND_MSK (SATR_MSK | SATG_MSK | SATB_MSK)
#ifdef USE_XBGR1555_FORMAT
#define OVFG_MSK 0x04000000
#define OVFR_MSK 0x00008000
#define OVFB_MSK 0x00000020
#define SATG_MSK 0x03E00000
#define SATR_MSK 0x00007C00
#define SATB_MSK 0x0000001F
#else
#define OVFG_MSK 0x08000000
#define OVFR_MSK 0x00010000
#define OVFB_MSK 0x00000020
#define SATG_MSK 0x07E00000
#define SATR_MSK 0x0000F800
#define SATB_MSK 0x0000001F
#endif
typedef enum
{
OBJ_BLEND, // No effects, just blend forced-blend pixels (ie. ST objects)
BLEND_ONLY, // Just alpha blending (if the pixels are 1st and 2nd target)
BLEND_BRIGHT, // Perform alpha blending if appropiate, and brighten otherwise
BLEND_DARK, // Same but with darken effecg
} blendtype;
// Applies blending (and optional brighten/darken) effect to a bunch of
// color-indexed pixel pairs. Depending on the mode and the pixel target
// number, blending, darken/brighten or no effect will be applied.
// Bits 0-8 encode the color index (paletted colors)
// Bit 9 is set if the pixel belongs to a 1st target layer
// Bit 10 is set if the pixel belongs to a 2nd target layer
// Bit 11 is set if the pixel belongs to a ST-object
template <blendtype bldtype, bool st_objs>
static void merge_blend(u32 start, u32 end, u16 *dst, u32 *src) {
u32 bldalpha = read_ioreg(REG_BLDALPHA);
u32 brightf = MIN(16, read_ioreg(REG_BLDY) & 0x1F);
u32 blend_a = MIN(16, (bldalpha >> 0) & 0x1F);
u32 blend_b = MIN(16, (bldalpha >> 8) & 0x1F);
bool can_saturate = blend_a + blend_b > 16;
if (can_saturate) {
// If blending can result in saturation, we need to clamp output values.
while (start < end) {
u32 pixpair = src[start];
// If ST-OBJ, force blending mode (has priority over other effects).
// If regular blending mode, blend if 1st/2nd bits are set respectively.
// Otherwise, apply other color effects if 1st bit is set.
bool force_blend = (pixpair & 0x04000800) == 0x04000800;
bool do_blend = (pixpair & 0x04000200) == 0x04000200;
if ((st_objs && force_blend) || (do_blend && bldtype == BLEND_ONLY)) {
// Top pixel is 1st target, pixel below is 2nd target. Blend!
u16 p1 = palette_ram_converted[(pixpair >> 0) & 0x1FF];
u16 p2 = palette_ram_converted[(pixpair >> 16) & 0x1FF];
u32 p1e = (p1 | (p1 << 16)) & BLND_MSK;
u32 p2e = (p2 | (p2 << 16)) & BLND_MSK;
u32 pfe = (((p1e * blend_a) + (p2e * blend_b)) >> 4);
// If the overflow bit is set, saturate (set) all bits to one.
if (pfe & (OVFR_MSK | OVFG_MSK | OVFB_MSK)) {
if (pfe & OVFG_MSK)
pfe |= SATG_MSK;
if (pfe & OVFR_MSK)
pfe |= SATR_MSK;
if (pfe & OVFB_MSK)
pfe |= SATB_MSK;
}
pfe &= BLND_MSK;
dst[start++] = (pfe >> 16) | pfe;
}
else if ((bldtype == BLEND_DARK || bldtype == BLEND_BRIGHT) &&
(pixpair & 0x200) == 0x200) {
// Top pixel is 1st-target, can still apply bright/dark effect.
u16 pidx = palette_ram_converted[pixpair & 0x1FF];
u32 epixel = (pidx | (pidx << 16)) & BLND_MSK;
u32 pa = bldtype == BLEND_DARK ? 0 : ((BLND_MSK * brightf) >> 4) & BLND_MSK;
u32 pb = ((epixel * (16 - brightf)) >> 4) & BLND_MSK;
epixel = (pa + pb) & BLND_MSK;
dst[start++] = (epixel >> 16) | epixel;
}
else {
dst[start++] = palette_ram_converted[pixpair & 0x1FF]; // No effects
}
}
} else {
while (start < end) {
u32 pixpair = src[start];
bool do_blend = (pixpair & 0x04000200) == 0x04000200;
bool force_blend = (pixpair & 0x04000800) == 0x04000800;
if ((st_objs && force_blend) || (do_blend && bldtype == BLEND_ONLY)) {
// Top pixel is 1st target, pixel below is 2nd target. Blend!
u16 p1 = palette_ram_converted[(pixpair >> 0) & 0x1FF];
u16 p2 = palette_ram_converted[(pixpair >> 16) & 0x1FF];
u32 p1e = (p1 | (p1 << 16)) & BLND_MSK;
u32 p2e = (p2 | (p2 << 16)) & BLND_MSK;
u32 pfe = (((p1e * blend_a) + (p2e * blend_b)) >> 4) & BLND_MSK;
dst[start++] = (pfe >> 16) | pfe;
}
else if ((bldtype == BLEND_DARK || bldtype == BLEND_BRIGHT) &&
(pixpair & 0x200) == 0x200) {
// Top pixel is 1st-target, can still apply bright/dark effect.
u16 pidx = palette_ram_converted[pixpair & 0x1FF];
u32 epixel = (pidx | (pidx << 16)) & BLND_MSK;
u32 pa = bldtype == BLEND_DARK ? 0 : ((BLND_MSK * brightf) >> 4) & BLND_MSK;
u32 pb = ((epixel * (16 - brightf)) >> 4) & BLND_MSK;
epixel = (pa + pb) & BLND_MSK;
dst[start++] = (epixel >> 16) | epixel;
}
else {
dst[start++] = palette_ram_converted[pixpair & 0x1FF]; // No effects
}
}
}
}
// Applies brighten/darken effect to a bunch of color-indexed pixels.
template <blendtype bldtype>
static void merge_brightness(u32 start, u32 end, u16 *srcdst) {
u32 brightness = MIN(16, read_ioreg(REG_BLDY) & 0x1F);
while (start < end) {
u16 spix = srcdst[start];
u16 pixcol = palette_ram_converted[spix & 0x1FF];
if ((spix & 0x200) == 0x200) {
// Pixel is 1st target, can apply color effect.
u32 epixel = (pixcol | (pixcol << 16)) & BLND_MSK;
u32 pa = bldtype == BLEND_DARK ? 0 : ((BLND_MSK * brightness) >> 4) & BLND_MSK; // B/W
u32 pb = ((epixel * (16 - brightness)) >> 4) & BLND_MSK; // Pixel color
epixel = (pa + pb) & BLND_MSK;
pixcol = (epixel >> 16) | epixel;
}
srcdst[start++] = pixcol;
}
}
// Fills a segment using the backdrop color (in the right mode).
template<rendtype rdmode, typename dsttype>
void fill_line_background(u32 start, u32 end, dsttype *scanline) {
while (start < end)
if (rdmode == FULLCOLOR)
scanline[start++] = palette_ram_converted[0];
else
scanline[start++] = 0;
}
// Renders the backdrop color (ie. whenever no layer is active) applying
// any effects that might still apply (usually darken/brighten).
static void render_backdrop(u32 start, u32 end, u16 *scanline) {
u16 bldcnt = read_ioreg(REG_BLDCNT);
u16 pixcol = palette_ram_converted[0];
u32 effect = (bldcnt >> 6) & 0x03;
u32 bd_1st_target = ((bldcnt >> 0x5) & 0x01);
if (bd_1st_target && effect == COL_EFFECT_BRIGHT) {
u32 brightness = MIN(16, read_ioreg(REG_BLDY) & 0x1F);
// Unpack 16 bit pixel for fast blending operation
u32 epixel = (pixcol | (pixcol << 16)) & BLND_MSK;
u32 pa = ((BLND_MSK * brightness) >> 4) & BLND_MSK; // White color
u32 pb = ((epixel * (16 - brightness)) >> 4) & BLND_MSK; // Pixel color
epixel = (pa + pb) & BLND_MSK;
pixcol = (epixel >> 16) | epixel;
}
else if (bd_1st_target && effect == COL_EFFECT_DARK) {
u32 brightness = MIN(16, read_ioreg(REG_BLDY) & 0x1F);
u32 epixel = (pixcol | (pixcol << 16)) & BLND_MSK;
epixel = ((epixel * (16 - brightness)) >> 4) & BLND_MSK; // Pixel color
pixcol = (epixel >> 16) | epixel;
}
// Fill the line with that color
while (start < end)
scanline[start++] = pixcol;
}
// Renders all the available and enabled layers (in tiled mode).
// Walks the list of layers in visibility order and renders them in the
// specified mode (taking into consideration the first layer, etc).
template<rendtype bgmode, rendtype objmode, typename dsttype>
void render_layers(u32 start, u32 end, dsttype *dst_ptr, u32 enabled_layers) {
u32 lnum;
u32 base_done = 0;
u16 dispcnt = read_ioreg(REG_DISPCNT);
u16 video_mode = dispcnt & 0x07;
bool obj_enabled = (enabled_layers & 0x10); // Objects are visible
bool objlayer_is_1st_tgt = ((read_ioreg(REG_BLDCNT) >> 4) & 1) != 0;
bool has_trans_obj = obj_alpha_count[read_ioreg(REG_VCOUNT)];
for (lnum = 0; lnum < layer_count; lnum++) {
u32 layer = layer_order[lnum];
bool is_obj = layer & 0x4;
if (is_obj && obj_enabled) {
bool can_skip_blend = !has_trans_obj && !objlayer_is_1st_tgt;
// If it's the first layer, make sure to fill with backdrop color.
if (!base_done)
fill_line_background<bgmode, dsttype>(start, end, dst_ptr);
// Optimization: skip blending mode if no blending can happen to this layer
if (objmode == STCKCOLOR && can_skip_blend)
render_scanline_objs<dsttype, INDXCOLOR>(layer & 0x3, start, end, dst_ptr);
else
render_scanline_objs<dsttype, objmode>(layer & 0x3, start, end, dst_ptr);
base_done = 1;
}
else if (!is_obj && ((1 << layer) & enabled_layers)) {
bool layer_is_1st_tgt = ((read_ioreg(REG_BLDCNT) >> layer) & 1) != 0;
bool can_skip_blend = !has_trans_obj && !layer_is_1st_tgt;
bool is8bpp = (read_ioreg(REG_BGxCNT(layer)) & 0x80); // 8 vs 4bpp
bool is_affine = (video_mode >= 1) && (layer >= 2);
u32 fnidx = (base_done) | (is_affine ? 2 : 0) | (is8bpp ? 4 : 0);
// Can optimize rendering if no blending can really happen.
// If stack mode, no blending and not base layer, we might speed up a bit
if (bgmode == STCKCOLOR && can_skip_blend) {
static const tile_render_function rdfns[8] = {
render_scanline_text<dsttype, INDXCOLOR, true, false>,
render_scanline_text<dsttype, INDXCOLOR, false, false>,
render_scanline_affine<dsttype, INDXCOLOR, true>,
render_scanline_affine<dsttype, INDXCOLOR, false>,
render_scanline_text<dsttype, INDXCOLOR, true, true>,
render_scanline_text<dsttype, INDXCOLOR, false, true>,
render_scanline_affine<dsttype, INDXCOLOR, true>,
render_scanline_affine<dsttype, INDXCOLOR, false>,
};
rdfns[fnidx](layer, start, end, dst_ptr);
} else {
static const tile_render_function rdfns[8] = {
render_scanline_text<dsttype, bgmode, true, false>,
render_scanline_text<dsttype, bgmode, false, false>,
render_scanline_affine<dsttype, bgmode, true>,
render_scanline_affine<dsttype, bgmode, false>,
render_scanline_text<dsttype, bgmode, true, true>,
render_scanline_text<dsttype, bgmode, false, true>,
render_scanline_affine<dsttype, bgmode, true>,
render_scanline_affine<dsttype, bgmode, false>,
};
rdfns[fnidx](layer, start, end, dst_ptr);
}
base_done = 1;
}
}
// Render background if we did not render any active layer.
if (!base_done)
fill_line_background<bgmode, dsttype>(start, end, dst_ptr);
}
// Renders a partial scanline without using any coloring effects (with the
// exception of OBJ blending).
static void render_color_no_effect(
u32 start, u32 end, u16* scanline, u32 enable_flags
) {
bool obj_blend = obj_alpha_count[read_ioreg(REG_VCOUNT)] > 0;
// Default rendering mode, without layer effects (except perhaps sprites).
if (obj_blend) {
u32 screen_buffer[240];
render_layers<INDXCOLOR, STCKCOLOR, u32>(start, end, screen_buffer, enable_flags);
merge_blend<OBJ_BLEND, true>(start, end, scanline, screen_buffer);
} else {
render_layers<FULLCOLOR, FULLCOLOR, u16>(start, end, scanline, enable_flags);
}
}
// Renders all layers honoring color effects (blending, brighten/darken).
// It uses different rendering routines depending on the coloring effect
// requirements, speeding up common cases where no effects are used.
// No effects use NORMAL mode (RBB565 color is written on the buffer).
// For blending, we use BLEND mode to record the two top-most pixels.
// For other effects we use COLOR16, which records an indexed color in the
// buffer (used for darken/brighten effects at later passes) or COLOR32,
// which similarly uses an indexed color for rendering but recording one
// color for the background and another one for the object layer.
static void render_color_effect(
u32 start, u32 end, u16* scanline, u32 enable_flags = 0x1F /* all enabled */
) {
bool obj_blend = obj_alpha_count[read_ioreg(REG_VCOUNT)] > 0;
u16 bldcnt = read_ioreg(REG_BLDCNT);
switch((bldcnt >> 6) & 0x03) {
case COL_EFFECT_BRIGHT:
{
// If no layers are 1st target, no effect will really happen.
bool some_1st_tgt = (read_ioreg(REG_BLDCNT) & 0x3F) != 0;
// If the factor is zero, it's the same as "regular" rendering.
bool non_zero_blend = (read_ioreg(REG_BLDY) & 0x1F) != 0;
if (some_1st_tgt && non_zero_blend) {
if (obj_blend) {
u32 screen_buffer[240];
render_layers<INDXCOLOR, STCKCOLOR, u32>(start, end, screen_buffer, enable_flags);
merge_blend<BLEND_BRIGHT, true>(start, end, scanline, screen_buffer);
} else {
render_layers<INDXCOLOR, INDXCOLOR, u16>(start, end, scanline, enable_flags);
merge_brightness<BLEND_BRIGHT>(start, end, scanline);
}
return;
}
}
break;
case COL_EFFECT_DARK:
{
// If no layers are 1st target, no effect will really happen.
bool some_1st_tgt = (read_ioreg(REG_BLDCNT) & 0x3F) != 0;
// If the factor is zero, it's the same as "regular" rendering.
bool non_zero_blend = (read_ioreg(REG_BLDY) & 0x1F) != 0;
if (some_1st_tgt && non_zero_blend) {
if (obj_blend) {
u32 screen_buffer[240];
render_layers<INDXCOLOR, STCKCOLOR, u32>(start, end, screen_buffer, enable_flags);
merge_blend<BLEND_DARK, true>(start, end, scanline, screen_buffer);
} else {
render_layers<INDXCOLOR, INDXCOLOR, u16>(start, end, scanline, enable_flags);
merge_brightness<BLEND_DARK>(start, end, scanline);
}
return;
}
}
break;
case COL_EFFECT_BLEND:
{
// If no layers are 1st or 2nd target, no effect will really happen.
bool some_1st_tgt = (read_ioreg(REG_BLDCNT) & 0x003F) != 0;
bool some_2nd_tgt = (read_ioreg(REG_BLDCNT) & 0x3F00) != 0;
// If 1st target is 100% opacity and 2nd is 0%, just render regularly.
bool non_trns_tgt = (read_ioreg(REG_BLDALPHA) & 0x1F1F) != 0x001F;
if (some_1st_tgt && some_2nd_tgt && non_trns_tgt) {
u32 screen_buffer[240];
render_layers<STCKCOLOR, STCKCOLOR, u32>(start, end, screen_buffer, enable_flags);
if (obj_blend)
merge_blend<BLEND_ONLY, true>(start, end, scanline, screen_buffer);
else
merge_blend<BLEND_ONLY, false>(start, end, scanline, screen_buffer);
return;
}
}
break;
case COL_EFFECT_NONE:
// Default case, see below.
break;
};
// Default case, just a regular no-effects render.
render_color_no_effect(start, end, scanline, enable_flags);
}
// Render all of the BG and OBJ in a tiled scanline from start to end ONLY if
// enable_flag allows that layer/OBJ. Also conditionally render color effects.
static void render_conditional_tile(
u32 start, u32 end, u16 *scanline, u32 enable_flags)
{
if (layer_count && (enable_flags & 0x1F)) {
bool effects_enabled = enable_flags & 0x20; // Window bit for effects.
if (effects_enabled)
render_color_effect(start, end, scanline, enable_flags);
else
render_color_no_effect(start, end, scanline, enable_flags);
}
else
render_backdrop(start, end, scanline);
}
// Render the BG and OBJ in a bitmap scanline from start to end ONLY if
// enable_flag allows that layer/OBJ. Also conditionally render color effects.
static void render_conditional_bitmap(
u32 start, u32 end, u16 *scanline, u32 enable_flags)
{
u16 dispcnt = read_ioreg(REG_DISPCNT);
const bitmap_layer_render_struct *layer_renderers =
&bitmap_mode_renderers[(dispcnt & 0x07) - 3];
u32 current_layer;
u32 layer_order_pos;
fill_line_background<FULLCOLOR, u16>(start, end, scanline);
for(layer_order_pos = 0; layer_order_pos < layer_count; layer_order_pos++)
{
current_layer = layer_order[layer_order_pos];
if(current_layer & 0x04)
{
if(enable_flags & 0x10)
render_scanline_objs<u16, FULLCOLOR>(current_layer & 3, start, end, scanline);
}
else
{
if(enable_flags & 0x04) {
s32 dx = (s16)read_ioreg(REG_BG2PA);
s32 dy = (s16)read_ioreg(REG_BG2PC);
if (dy)
layer_renderers->affine_render(start, end, scanline);
else if (dx == 256)
layer_renderers->blit_render(start, end, scanline);
else
layer_renderers->scale_render(start, end, scanline);
}
}
}
}
static inline void render_scanline_conditional(
u32 start, u32 end, u16 *scanline, u32 enable_flags = 0x3F)
{
u16 dispcnt = read_ioreg(REG_DISPCNT);
u32 video_mode = dispcnt & 0x07;
// Modes 0..2 are tiled modes, 3..5 are bitmap-based modes.
if(video_mode < 3)
render_conditional_tile(start, end, scanline, enable_flags);
else
render_conditional_bitmap(start, end, scanline, enable_flags);
}
// Renders the are outside of all active windows
static void render_windowout_pass(u16 *scanline, u32 start, u32 end)
{
u32 winout = read_ioreg(REG_WINOUT);
u32 wndout_enable = winout & 0x3F;
render_scanline_conditional(start, end, scanline, wndout_enable);
}
// Renders window-obj. This is a pixel-level windowing effect, based on sprites
// (objects) with a special rendering mode (the sprites are not themselves
// visible but rather "enable" other pixels to be rendered conditionally).
static void render_windowobj_pass(u16 *scanline, u32 start, u32 end)
{
u32 winout = read_ioreg(REG_WINOUT);
u32 wndout_enable = winout & 0x3F;
// First we render the "window-out" segment.
render_scanline_conditional(start, end, scanline, wndout_enable);
// Now we render the objects in "copy" mode. This renders the scanline in
// WinObj-mode to a temporary buffer and performs a "copy-mode" render.
// In this mode, we copy pixels from the temp buffer to the final buffer
// whenever an object pixel is rendered.
render_scanline_objs<u16, PIXCOPY>(4, start, end, scanline);
// TODO: Evaluate whether it's better to render the whole line and copy,
// or render subsegments and copy as we go (depends on the pixel/obj count)
}
// If the window Y coordinates are out of the window range we can skip
// rendering the inside of the window.
inline bool in_window_y(u32 vcount, u32 top, u32 bottom) {
// TODO: check if these are reversed when top-bottom are also reversed.
if (top > 227) // This causes the window to be invisible
return false;
if (bottom > 227) // This makes it all visible
return true;
if (top > bottom) /* Reversed: if not in the "band" */
return vcount > top || vcount <= bottom;
return vcount >= top && vcount < bottom;
}
// Renders window 0/1. Checks boundaries and divides the segment into
// subsegments (if necessary) rendering each one in their right mode.
// outfn is called for "out-of-window" rendering.
template<window_render_function outfn, unsigned winnum>
static void render_window_n_pass(u16 *scanline, u32 start, u32 end)
{
u32 vcount = read_ioreg(REG_VCOUNT);
// Check the Y coordinates to check if they fall in the right row
u32 win_top = read_ioreg(REG_WINxV(winnum)) >> 8;
u32 win_bot = read_ioreg(REG_WINxV(winnum)) & 0xFF;
// Check the X coordinates and generate up to three segments
// Clip the coordinates to the [start, end) range.
u32 win_l = MAX(start, MIN(end, read_ioreg(REG_WINxH(winnum)) >> 8));
u32 win_r = MAX(start, MIN(end, read_ioreg(REG_WINxH(winnum)) & 0xFF));
if (!in_window_y(vcount, win_top, win_bot) || (win_l == win_r))
// WindowN is completely out, just render all out.
outfn(scanline, start, end);
else {
// Render window withtin the clipped range
// Enable bits for stuff inside the window (and outside)
u32 winin = read_ioreg(REG_WININ);
u32 wndn_enable = (winin >> (8 * winnum)) & 0x3F;
// If the window is defined upside down, the areas are inverted.
if (win_l < win_r) {
// Render [start, win_l) range (which is outside the window)
if (win_l != start)
outfn(scanline, start, win_l);
// Render the actual window0 pixels
render_scanline_conditional(win_l, win_r, scanline, wndn_enable);
// Render the [win_l, end] range (outside)
if (win_r != end)
outfn(scanline, win_r, end);
} else {
// Render [0, win_r) range (which is "inside" window0)
if (win_r != start)
render_scanline_conditional(start, win_r, scanline, wndn_enable);
// The actual window is now outside, render recursively
outfn(scanline, win_r, win_l);
// Render the [win_l, 240] range ("inside")
if (win_l != end)
render_scanline_conditional(win_l, end, scanline, wndn_enable);
}
}
}
// Renders a full scaleline, taking into consideration windowing effects.
// Breaks the rendering step into N steps, for each windowed region.
static void render_scanline_window(u16 *scanline)
{
u16 dispcnt = read_ioreg(REG_DISPCNT);
u32 win_ctrl = (dispcnt >> 13);
// Priority decoding for windows
switch (win_ctrl) {
case 0x0: // No windows are active.
render_scanline_conditional(0, 240, scanline);
break;
case 0x1: // Window 0
render_window_n_pass<render_windowout_pass, 0>(scanline, 0, 240);
break;
case 0x2: // Window 1
render_window_n_pass<render_windowout_pass, 1>(scanline, 0, 240);
break;
case 0x3: // Window 0 & 1
render_window_n_pass<render_window_n_pass<render_windowout_pass, 1>, 0>(scanline, 0, 240);
break;
case 0x4: // Window Obj
render_windowobj_pass(scanline, 0, 240);
break;
case 0x5: // Window 0 & Obj
render_window_n_pass<render_windowobj_pass, 0>(scanline, 0, 240);
break;
case 0x6: // Window 1 & Obj
render_window_n_pass<render_windowobj_pass, 1>(scanline, 0, 240);
break;
case 0x7: // Window 0, 1 & Obj
render_window_n_pass<render_window_n_pass<render_windowobj_pass, 1>, 0>(scanline, 0, 240);
break;
}
}
static const u8 active_layers[] = {
0x1F, // Mode 0, Tile BG0-3 and OBJ
0x17, // Mode 1, Tile BG0-2 and OBJ
0x1C, // Mode 2, Tile BG2-3 and OBJ
0x14, // Mode 3, BMP BG2 and OBJ
0x14, // Mode 4, BMP BG2 and OBJ
0x14, // Mode 5, BMP BG2 and OBJ
0, // Unused
0,
};
void update_scanline(void)
{
u32 pitch = get_screen_pitch();
u16 dispcnt = read_ioreg(REG_DISPCNT);
u32 vcount = read_ioreg(REG_VCOUNT);
u16 *screen_offset = get_screen_pixels() + (vcount * pitch);
u32 video_mode = dispcnt & 0x07;
if(skip_next_frame)
return;
// If OAM has been modified since the last scanline has been updated then
// reorder and reprofile the OBJ lists.
if(reg[OAM_UPDATED])
{
order_obj(video_mode);
reg[OAM_UPDATED] = 0;
}
order_layers((dispcnt >> 8) & active_layers[video_mode], vcount);
// If the screen is in in forced blank draw pure white.
if(dispcnt & 0x80)
memset(screen_offset, 0xff, 240*sizeof(u16));
else
render_scanline_window(screen_offset);
// Mode 0 does not use any affine params at all.
if (video_mode) {
affine_reference_x[0] += (s16)read_ioreg(REG_BG2PB);
affine_reference_y[0] += (s16)read_ioreg(REG_BG2PD);
affine_reference_x[1] += (s16)read_ioreg(REG_BG3PB);
affine_reference_y[1] += (s16)read_ioreg(REG_BG3PD);
}
}
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